1. Technical Field
The following description relates to special effect processing on a photographed image, and more particularly, to a technology for defocusing a background portion of the photographed image.
2. Description of the Related Art
When capturing a photograph, a user usually focuses on an interested object to be photographed. For example, in portrait photography, the effect of a defocused background is becoming very popular. With such an effect, the photographed object itself is enhanced while the background portion becomes blurred. However, many current digital photographing devices are not provided with a sensor and an aperture that are large enough to obtain the desirable photographing effect.
In order to obtain an image with defocused background, a similar optical photographing effect can be simulated by a post digital process inside the photographing device. However, when performing the related post digital process, the photographing device needs to photograph two or more images for extracting a background distribution of the photographed image, which may cause inconvenience for the user.
Furthermore, the effect achieved by the current background defocusing technology is typically limited by the intensity of the environment light. For example, the effect of the flash matting technology is limited by the influence of the flash on the photographed object. Moreover, the technique of depth from defocus requires a relatively large calculation amount, which is not desirable.